This disclosure is directed to methods for treating subterranean formations, such as hydraulic fracturing treatments and sand control, and in particular, use of lightweight polymers derived from cashew nut shell liquid as proppant material in hydraulic fracturing treatments or as particulate material in sand control methods such as gravel packing and frac pack treatments.
Hydraulic fracturing increases the flow of desirable fluids such as oil and gas from a subterranean formation and involves placing a fracturing fluid into a subterranean formation or zone at a rate and pressure sufficient to impart a stress in the formation or zone with attendant production of a fracture in the formation or zone.
Beyond creating the fracture, the fracturing fluid also transports a proppant into the fracture. The proppant keeps the fracture open after release of the exerted pressure. Further, the proppant establishes conductive means in which the formation fluids flow to the borehole. Since the proppant provides a higher conductivity than the surrounding rock, the fracture has greater potential for production of hydrocarbons.
Proppants used in the art include sand, glass beads, walnut hulls, and metal shot as well as polymer-coated sands, ceramics, sintered bauxite, and the like. In order to withstand high pressures downhole, the proppants must be of sufficient strength. The relative strength of proppants increases with their corresponding apparent specific gravity (ASG), typically ranging from 2.65 for sands to 3.4 for sintered bauxite. Unfortunately, increasing ASG leads directly to increasing degree of difficulty with proppant transport and reduced propped fracture volume, thereby reducing fracture conductivity.
More recently, ultra lightweight (ULW) materials have been used as proppants since they reduce the fluid velocity required to maintain proppant transport within the fracture, which, in turn, provides for a greater amount of the created fracture area to be propped. Despite all the advances in the art, there is a need for alternative lightweight proppants that exhibit high particle strength under high pressures. It would be a further advantage if such lightweight proppants have good chemical resistance and are stable at high temperatures. It would still be a further advantage if the lightweight proppants are spherical so that a proppant pack formed therefrom can have improved conductivity.